The first-hand knowledge: I have not had luck with Citronelle. It did not thrive in my Z4, Midwest garden (Twin Cities). I think it needs just the right spot - you know - "morning sun, afternoon shade, evenly moist well draining soil,..." and maybe a longer growing season. I talked to a TN gardener who had it growing in her hosta garden where it did just fine. I have had success with both Circus and Paris. Paris is great and I have multiplied it. I really like the long bloom period and the bright red blooms that stand straight up. Circus is ready for division this spring. I like the hot pink blooms but they flop for me. I think I will move it to a little sunnier spot and see if that helps.

Second-hand knowledge. Venero gardens, a beautiful display garden I visit annually, had a border of Rave on for years that was beautiful. I asked the owner about it once and she (Dory) said it grew well here. My sister bought Berry Timeless last year and the pink blooms where beautiful and standing straight up like Paris. It seems to have overwintered just fine, but it is a little early yet to give a recommendation. My sister has tried many Heuchera including Milan. She no longer has Milan - its hard to say whether it was the heuchera's fault or the difficult spot in which she was growing it.